The field of the invention pertains to light-weight portable mixers and, in particular, to hand-held powered mixers for thick heavy viscous liquids which may contain solids.
Typically, concrete, cement mortar, gypsum and other similar construction materials are mixed in stationary, truck or trailer mounted rotary bowls. The bowls are equipped with curved fins inside to assist in thoroughly mixing water with the powder and aggregates. Even the smallest bowl mixers are too heavy for one person to easily lift because of the weight of the steel bowl and attached motor. When a relatively small amount is needed these construction materials are typically hand mixed with a perforated hoe in a metal trough.
Despite the need for a truly portable powered hand-held mixer, apparently none are commercially available. An early apparently portable mixer is disclosed in U.S. Pat. No. 994,978. This mixer has an externally driven shaft with a plurality of curved mixing blades thereon. The material is mixed as the blades move the material parallel to the shaft to the outlet.
U.S. Pat. No. 3,166,303 discloses a plurality of blades on a vertical shaft as the mixing device. The shaft is powered by a portable electric drill and a vertical barrel is used to contain the mix. U.S. Pat. No. 3,185,451 also discloses an electric powered hand-held mixer having a pair of counter-rotating spiral wire blades. The mixer is used in a large mixing trough.
U.S. Pat. No. 4,761,076 and an advertising brochure from Sears, Roebuck & Co., Chicago, Ill. disclose a wheeled mixing tub equipped with an auger mixer. The auger is gasoline powered and mounted permanently to the tub in a manner that permits the auger to be moved from one side of the tub to the other. Thus, the mixer is not truly portable in the manner of a hand-held mixing device.